Systems and methods for controlling a motor

ABSTRACT

An interface module and methods for controlling a motor in a heating, ventilation, and air conditioning (HVAC) system are provided. The interface module is configured to determine an operating mode selected from a plurality of operating modes of the HVAC system based on at least one signal received from at least one of a first device and a second device, determine a motor operating parameter at which to operate the motor based on the determined operating mode, and control the motor in accordance with the motor operating parameter.

BACKGROUND

The embodiments described herein relate generally to motors, and more particularly, to systems and methods for controlling a motor in a heating, ventilation, air conditioning (HVAC) system.

Motors used in HVAC and fluid circulation systems often must be programmed to operate according to the specific needs of their systems and may need to be replaced when they do not operate properly or fail. Typically, the motors are programmed using a specialized motor programming computer by an Original Equipment Manufacturers (OEM) at a motor manufacturing facility, at the point of sale, or at an assembly plant.

OEMs that utilize configurable/intelligent motors configure each motor to meet the requirements of the specific product and the expected application. The functionality of the OEM system is derived from a combination of the motor's configuration and the operation of an HVAC system controller. For example, signal definitions/functions associated with a system controller wiring harness are determined by the motor's configuration. With each replacement configurable/intelligent motor needing to be ordered with the specific OEM system configuration, returning a failed system to operation may be a time consuming and expensive process.

BRIEF DESCRIPTION

In one aspect, an interface module configured to control a motor in a heating, ventilation, and air conditioning (HVAC) system is provided. The interface module is configured to determine an operating mode selected from a plurality of operating modes of the HVAC system based on at least one signal received from at least one of a first device and a second device, determine a motor operating parameter at which to operate the motor based on the determined operating mode, and control the motor in accordance with the motor operating parameter.

In another aspect, a method controlling a motor in a heating, ventilation, and air conditioning (HVAC) system using an interface module is provided. The method includes determining an operating mode selected from a plurality of operating modes of the HVAC system based on at least one signal received from at least one of a first device and a second device, determining a motor operating parameter at which to operate the motor based on the determined operating mode, and controlling the motor in accordance with the motor operating parameter.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic diagram of an exemplary HVAC system that includes an interface module for controlling a motor.

FIG. 2 is a flowchart of an exemplary method of controlling a motor using the interface module shown in FIG. 1.

DETAILED DESCRIPTION

FIG. 1 is a schematic diagram of a heating, ventilation, and air conditioning (HVAC) system 100 that includes an interface module 102 and a retrofit motor 104. HVAC system 100 also includes a thermostat 106 and a system controller 108. Interface module 102 is coupled to and configured to receive signals from both thermostat 106 and system controller 108. Further, interface module 102 is coupled to and configured to transmit signals to motor 104.

In the exemplary embodiment, motor 104 is an electronically commutated motor (ECM), which may also be referred to as a brushless direct current (DC) motor. Motor 104 is utilized as a fan and/or blower motor in HVAC system 100. Alternatively, motor 104 may be implemented in any other application including, but not limited to, a fluid (e.g., water, air, etc.) moving system, a clean room filtering system, a fan filter unit, a variable air volume system, a refrigeration system, a furnace system, and/or an air conditioning system. In the exemplary embodiment, HVAC system 100 is retrofit to include motor 104 that replaces an existing ECM or permanent split capacitor (PSC) motor (hereinafter referred to as “replaced motor”, not shown).

Thermostat 106 is configured to control a mode in which HVAC system 100 is operating, for example, a cooling mode, a heating mode, or a fan only mode, and/or at a first stage or at a second stage. Thus, in the exemplary embodiment, thermostat 106 includes plurality of thermostat leads 110 associated with one or more of a cooling output, a heating output, a fan output, a first stage output, and a second stage output. However, thermostat 106 is not limited to these outputs and may include any number of outputs that enables thermostat 106 to function as described herein. Thermostat 106 generates at least one thermostat signal that is transmitted to at least one of interface module 102 and system controller 108.

System controller 108 includes a system controller wiring harness 112 that was originally coupled to and configured to transmit instructions to the replaced motor. When interface module 102 is provided during the replacement process, system controller wiring harness 112 is coupled to and configured to communicate with interface module 102. For example, system controller 108 relays signals generated by thermostat 106 to interface module 102. More specifically, system controller 108 processes the thermostat signal and generates instructions for operating motor 104 that are provided to interface module 102. System controller 108 may also communicate with other input/output devices, such as humidity control systems, gas burner controls, gas ignition systems, other motors, safety systems, service systems, and/or combustion blowers. Accordingly, system controller 108 generates operating instructions for motor 104 based on signals received from thermostat 106, as well as signals received from alternative devices coupled to system controller 108, such as safety systems, ambient sensors, gas ignition systems, and other HVAC system components.

Interface module 102 receives signals from at least one of thermostat 106 and system controller 108. Based on the received signals, interface module 102 provides motor 104 with control signals. More specifically, interface module 102 receives signals from thermostat leads 110, as well as from system controller 108 via system controller wire harness 112, and is configured to provide motor 104 with a signal that selects a desired motor control profile.

In the exemplary embodiment, interface module 102 includes components mounted to a printed circuit board. More specifically, in the exemplary embodiment, interface module 102 includes a processing device 114, a memory device 116, a user interface 118, and a communication interface 120.

The term processing device, as used herein, refers to central processing units, microprocessors, microcontrollers, reduced instruction set circuits (RISC), application specific integrated circuits (ASIC), logic circuits, and any other circuit or processor capable of executing the functions described herein.

It should be noted that the embodiments described herein are not limited to any particular processor for performing the processing tasks of the invention. The term “processor,” as that term is used herein, is intended to denote any machine capable of performing the calculations, or computations, necessary to perform the tasks of the invention. The term “processor” also is intended to denote any machine that is capable of accepting a structured input and of processing the input in accordance with prescribed rules to produce an output. It should also be noted that the phrase “configured to” as used herein means that the processor is equipped with a combination of hardware and software for performing the tasks described herein, as will be understood by those skilled in the art.

Communication interface 120 may include an RS-485 connector, a digital serial interface (DSI) connector, a control wire reception terminal, and/or any other type of interface that allows a user, thermostat 106, and/or system controller 108 to provide a control signal to interface module 102. For example, the control signal may include a 0-10 volts direct current (VDC) control signal, a 0-5 VDC control signal, a 4-20 milliampere (mA) control signal, and/or any other type of control signal that allows interface module 102 to function as described herein.

In the exemplary embodiment, interface module 102 also includes memory device 116. Memory device 116 may be included within processing device 114, or may be coupled to processing device 114. In the exemplary embodiment, memory device 116 stores a plurality of different communications protocols. For example, processing device 114 may access the communications protocols stored in memory device 116 in order to translate a signal received from a user via communication interface 120 into a format that may be transmitted to motor 104. More specifically, processing device 114 may receive a signal sent using an Ethernet protocol, in which motor 104 may not be compatible. Processing device 114 translates the received signal to a communication suitable to be transmitted to motor 104.

Interface module 102 includes a user interface 118 that enables user-interaction with interface module 102 and enables interface module 102 to provide feedback with regards to its operation. User interface 118 facilitates configuration (i.e., setup) of interface module 102. Original ECM functionality that is being replicated by interface module 102 is enabled via user interface 118. User interface 118 further enables selection of operational values such as “ON” delay times, “OFF” delay times, duty cycle values, etc.

User interface 118 includes a plurality of buttons/switches and a display. The display provides information relating to the operation of interface module 102 including, but not limited to, system control signals status, thermostat signals status, system operating mode, motor torque percent, and/or delay activity. The display is also configured to provide diagnostic (e.g., system health) and self-test information.

Alternatively, interface module 102 may be implemented as a “black box” void of any buttons/switches or display. In this implementation, interface module 102 communicates with an intelligent wireless device (e.g., smartphone, tablet, PDA, etc., not shown) using wireless communication (e.g., Wi-Fi, Bluetooth, RFID, etc.) via communication interface 120. The wireless device runs/executes an application that provides user interface 118 and feedback functions.

Interface module 102 is configured to determine an operating mode of HVAC system 100 (heat, cool, etc.). When the configuration of the replaced motor and the operations of system controller 108 are unknown, thermostat signals and the motor control signals from system controller 108 enable determination of the operating mode of HVAC system 100. Interface module 102 continuously or periodically monitors an aggregate signal of the system controller signals and the thermostat signals, and compares the resulting aggregate signal with stored reference information to determine the operating mode of the system.

In the exemplary embodiment, to acquire the information necessary for determining the system operating mode, interface module 102 is configured to “learn” the HVAC system's operation by implementing a learning algorithm that, over time, enables interface module 102 to recognize and store as a reference the system and thermostat signal combinations and timing that are used to resolve the operating mode of HVAC system 100. In some embodiments, interface module 102 is configured to discriminate between discrete and variable speed motor control as well as recognize a single stage thermostat that is paired with a dual stage system.

In another embodiment, the information necessary for determining the system operating mode is acquired by teaching interface module 102 to recognize system and thermostat signal combinations. While exercising HVAC system 100 throughout its different modes of operation, the installer manually triggers interface module 102 to capture a “snapshot” of the available inputs for each mode of operation. Interface module 102 correlates each mode of operation with a respective snapshot to identify the system operating modes. A snapshot is a unique combination of states of individual system and thermostat signals, i.e., inputs.

In yet another embodiment, interface module 102 acquires the information necessary for determining the system operating mode via manual configuration of interface module 102 with the appropriate information by a technician or installer of motor 104.

Interface module 102 is configured to implement “ON” delays and “OFF” delays in HVAC systems that allocate this functionality to motor 104. More specifically, interface module 102 facilitates enabling/disabling and/or selecting time values for ON delays and OFF delays for the appropriate system operating modes in order to complete/replicate the HVAC system performance.

Interface module 102 is configured to provide feedback to be utilized by HVAC system 100 to satisfy expectations of system controller 108. Specifically, interface module 102 facilitates enabling/disabling and/or selecting one of a plurality of available motor output signal types. This feature is realized by pairing interface module 102 with a known retrofit/replacement motor that provides a fundamental motor output signal that interface module 102 modifies based on its configuration and passes on to system controller 108.

Interface module 102 is further configured to control motor 104. In operating motor 104, interface module 102 provides a control signal to motor 104 based on signals received from thermostat 106 and system controller 108. In the exemplary embodiment, motor 104 is a “communicating” ECM motor and interface module 102 controls motor 104 using commands. For example, the physical layer of interface module 102 may include serial, controller area network (CAN), wireless, bus, and/or any other standard communications interface/protocol. Interface module 102 provides a single control signal that includes an industry recognized, standard PWM signal to drive motor 104. A duty cycle of the control signal corresponds to a percent of full torque that may be generated by motor 104.

In an alternative embodiment, where motor 104 may need unique programming, such as field programming, for each system, interface module 102 is configured to provide a 0 to 10 Vdc control signal to motor 104.

Interface module 102 in combination with motor 104 is configured to affect airflow that assures safe operation of HVAC system 100. Interface module 102 maintains (e.g., in non-volatile memory) a duty cycle value for each operating mode of HVAC system 100. Initially, default values are used to operate motor 104. During installation, a service technician verifies the airflow in all operating modes to ensure that the temperature rise of fossil fuel heating systems and the CFM per ton of cooling meet OEM specifications. Interface module 102 provides a user interface 118 for making adjustments to the stored duty cycle values as determined by the technician.

FIG. 2 is a flowchart of an exemplary method 200 of controlling a motor in a HVAC system using interface module 102 (shown in FIG. 1).

Initially, method 200 includes determining 202 an operating mode of a plurality of operating modes of the HVAC system based on at least one signal received from at least one of a first device and a second device. In some embodiments, the first device may be a thermostat and the second device may be a system controller of the HVAC system. Method 200 also includes determining 204 a motor operating parameter at which to control the motor based on the determined operating mode. Method 200 further includes operating 206 the motor in accordance with the motor operating parameter.

In one embodiment, method 200 may include continuously monitoring an aggregate signal of the system controller signals and the thermostat signals, and comparing the resulting aggregate signal with stored reference information to determine the operating mode of the HVAC system.

In another embodiment, to determine the operating mode of the HVAC system, method 200 may include implementing, by the interface module, an algorithm that, over time, recognizes and stores as a reference, the first and second device signal combinations and timing.

In another embodiment, wherein to operate the motor, method 200 may include transmitting a pulse width modulation (PWM) signal that represents the motor operating parameter, wherein a duty cycle of the PWM signal corresponds to a percent of full torque that may be generated by motor.

In another embodiment, method 200 may include receiving, via a user interface of the interface module, operational values input by a user, the operational values including at least one of ON delay times, OFF delay times, and duty cycle values, and implementing the operational values prior to operating the motor.

The embodiments described herein provide an interface module and methods of controlling a motor. The embodiments facilitate determining an operating mode of a plurality of operating modes of the HVAC system based on at least one signal received from at least one of a first device and a second device, determining a motor operating parameter at which to operate the motor based on the determined operating mode, and controlling the motor in accordance with the motor operating parameter. The interface module facilitates replacing or retrofitting a failed motor in a HVAC system with a readily available, stock, retrofit/replacement motor. The interface module provides a cost-effective solution to interfacing between HVAC system controllers, thermostats and replacement motors. Further, the interface module facilitates returning a failed HVAC system to operation quickly and efficiently (e.g., in one service call).

Exemplary embodiments of the interface module and methods of controlling a motor are described above in detail. The interface module and methods are not limited to the specific embodiments described herein, but rather, components of the interface module and/or steps of the method may be utilized independently and separately from other components and/or steps described herein. For example, the control system and methods may also be used in combination with other motor systems and methods, and are not limited to practice with only the HVAC system as described herein. Rather, the exemplary embodiments can be implemented and utilized in connection with many other system applications or other support.

A technical effect of the system described herein includes at least one of: (a) determining an operating mode of a plurality of operating modes of the HVAC system based on at least one signal received from at least one of a first device and a second device; (b) determining a motor operating parameter at which to operate the motor based on the determined operating mode; (c) controlling the motor in accordance with the motor operating parameter; (d) replacing or retrofitting a failed motor in a HVAC system with a readily available, stock, retrofit/replacement motor; (e) provides a cost-effective solution to interfacing between HVAC system controllers, thermostats and replacement motors; and (f) facilitates returning a failed HVAC system to operation quickly and efficiently.

Although specific features of various embodiments of the invention may be shown in some drawings and not in others, this is for convenience only. In accordance with the principles of the invention, any feature of a drawing may be referenced and/or claimed in combination with any feature of any other drawing.

This written description uses examples to disclose the invention, including the best mode, and also to enable any person skilled in the art to practice the invention, including making and using any layers or systems and performing any incorporated methods. The patentable scope of the invention is defined by the claims, and may include other examples that occur to those skilled in the art. Such other examples are intended to be within the scope of the claims if they have structural elements that do not differ from the literal language of the claims, or if they include equivalent structural elements with insubstantial differences from the literal language of the claims. 

What is claimed is:
 1. An interface module configured to control a motor in a heating, ventilation, and air conditioning (HVAC) system, said interface module configured to: determine an operating mode selected from a plurality of operating modes of the HVAC system based on at least one signal received from at least one of a first device and a second device; determine a motor operating parameter at which to operate the motor based on the determined operating mode; and control the motor in accordance with the motor operating parameter.
 2. The interface module of claim 1, wherein to determine the operating mode of the HVAC system, said interface module is configured to: continuously monitor an aggregate signal of the system controller signals and the thermostat signals; and compare the resulting aggregate signal with stored reference information to determine the operating mode of the HVAC system.
 3. The interface module of claim 1, wherein to determine the operating mode of the HVAC system, said interface module is configured to implement an algorithm that, over time, recognizes and stores as a reference, the first and second device signal combinations and timing.
 4. The interface module of claim 1, wherein to determine the operating mode of the HVAC system, said interface module is configured to: capture input data associated with available inputs for each mode of operation while the HVAC system is exercised through its modes of operation; and correlate each mode of operation with respective input data to identify the HVAC system operating modes.
 5. The interface module of claim 1, wherein to determine the operating mode of the HVAC system, said interface module is configured to receive and store information for each operating mode input by a technician.
 6. The interface module of claim 1, wherein said interface module is further configured to implement one of an ON delay and an OFF delay required by the determined operating mode before transmitting the control signal to the motor.
 7. The interface module of claim 1, wherein the second device is a system controller, and wherein said interface module is further configured to provide feedback to be utilized by the HVAC system to satisfy expectations of the system controller.
 8. The interface module of claim 7, wherein said interface module is further configured to facilitate at least one of enabling, disabling, and selecting one of a plurality of available motor output signal types.
 9. The interface module of claim 1, wherein to operate the motor, said interface module is configured to transmit a control signal to the motor that includes the motor operating parameter.
 10. The interface module of claim 1, wherein to control the motor, said interface module is configured to transmit a pulse width modulation (PWM) signal that represents the motor operating parameter.
 11. The interface module of claim 10, wherein a duty cycle of the PWM signal corresponds to a percent of full torque that may be generated by motor.
 12. The interface module of claim 1, wherein to control the motor, said interface module is configured to transmit a 0 to 10 Vdc control signal to the motor.
 13. The interface module of claim 1, wherein said interface module comprises a user interface configured to provide information to a user relating to operation of said interface module, the information including at least one of system control signals status, thermostat signals status, system operating mode, motor torque percent, and delay activity.
 14. The interface module of claim 1, wherein said interface module comprises a user interface configured to provide at least one of system health diagnostic information and self-test information.
 15. The interface module of claim 1, wherein said interface module comprises a user interface configured to receive operational values input by a user, the operational values including at least one of ON delay times, OFF delay times, and duty cycle values.
 16. A method of controlling a motor in a heating, ventilation, and air conditioning (HVAC) system using an interface module, said method comprising: determining an operating mode selected from a plurality of operating modes of the HVAC system based on at least one signal received from at least one of a first device and a second device; determining a motor operating parameter at which to operate the motor based on the determined operating mode; and controlling the motor in accordance with the motor operating parameter.
 17. The method of claim 16, wherein determining the operating mode of the HVAC system comprises: continuously monitoring an aggregate signal of the system controller signals and the thermostat signals; and comparing the resulting aggregate signal with stored reference information to determine the operating mode of the HVAC system.
 18. The method of claim 16, wherein determining the operating mode of the HVAC system comprises implementing, by the interface module, an algorithm that, over time, recognizes and stores as a reference, the first and second device signal combinations and timing.
 19. The method of claim 16, wherein controlling the motor comprises transmitting a pulse width modulation (PWM) signal that represents the motor operating parameter, wherein a duty cycle of the PWM signal corresponds to a percent of full torque that may be generated by motor.
 20. The method of claim 16, further comprising: receiving, via a user interface of the interface module, operational values input by a user, the operational values including at least one of ON delay times, OFF delay times, and duty cycle values; and implementing the operational values prior to operating the motor. 